1. Field of the Invention
The present invention relates to a non-contact type IC card and a method of manufacturing such a card. More particularly, the present invention relates to a non-contact type IC card using a plane coil in which a conductor is wound on substantially the same plane a plurality of times, and the terminals of the plane coil are electrically connected to the electrode terminals of a semiconductor element.
2. Description of the Related Art
As shown in FIG. 8, an IC card includes: a rectangular-shaped plane coil 100 in which a conductor wire 102 is wound a plurality of times; and a semiconductor element 104. The plane coil 100 and the semiconductor element 104 are interposed between two sheets of resin film 106 made of polyvinyl chloride (PVC) on which letters and other marks are printed. The two sheets of resin film 106 are made to adhere by an adhesive layer made of polyurethane resin. This adhesive layer seals the plane coil 100 and the semiconductor element 104.
When the thus formed IC card moves along a magnetic field formed by a card processor, electric power is generated by electromagnetic induction caused in the plane coil 100 of the IC card. Therefore, the semiconductor element 104 is started by the generated electric power, so that communication can be passed and received between the semiconductor element 104 of the IC card and the card processor via the plane coil 100 which functions as an antenna.
The plane coil 100 used for the above IC card is conventionally formed in such a manner that a covered electric wire is wound a plurality of times.
However, when the covered electric wire is wound so as to form the plane coil 100, it is difficult to reduce the manufacturing cost of the plane coil 100 and it is also difficult to mass-produce.
Therefore, a plane coil is formed by means of punching or etching a thin metal plate, by which the plane coil can be mass-produced at low cost as compared with a plane coil formed by winding a covered wire.
However, a plane coil made by etching or punching a thin metal plate has a drawback in that handling it is relatively difficult. More specifically, as shown in FIG. 9(a), when no external force is exerted on a plane coil made by etching or punching a thin metal plate, a predetermined interval is maintained between the adjacent loops of conductor 102 in the inside/outside direction of the plane coil 100. Contrary to this, as shown in FIG. 9(b), if a lateral external force F is exerted on the plane coil 100, the conductor 102 may be deformed and the adjacent loops of conductor may come into contact with each other, thereby causing a short circuit.
Such contact between adjacent loops of the conductor due to deformation thereof may occur if an external force is exerted on the plane coil during a manufacturing process of the IC card, such as when the plane coil 100 is transported from place to place or received in some place, or if an external force caused by flow of adhesive acts laterally on the conductor 102 when the plane coil is adhered to a resin film provided on one surface thereof with an adhesive.
In order to prevent such electrical contact between adjacent loops of the conductor due to deformation thereof and to manufacture an IC card, the inventors of this application have proposed to use an improved IC card lead frame in a manufacturing process of an IC card.
The improved lead frame for an IC card is made by etching or punching a thin metal sheet, in such a manner that each plane coil is partially connected with the inside frame and the outside frame which are respectively formed inside and outside, leaving a predetermined interval between the plane coil and the inside and outside frames. Specifically, the support sections extending from a plurality of positions of the inside edge of the outside frame are respectively connected with the outermost conductor of the plane coil, and the support sections extending from a plurality of positions of the outside edge of the inside frame are respectively connected with the innermost conductor of the plane coil.
The plane coil is substantially rectangular. In order to enhance the rigidity of the plane coil, there are provided bent sections in each straight line section of the plane coil. Further, in order to integrate the conductors on the circumference of the plane coil into one body so as to prevent the conductors from breaking up, the conductors on the circumference, which are adjacent to each other, are connected with each other by the connecting pieces, which are arranged at a plurality of positions.
When the plane coil is separated from the inside frame and the outside frame, the support sections are cut off, as are the connecting pieces. After they have been cut off from the plane coil, the conductors on the circumference of the plane coil tend to break up. Therefore, in order to prevent the conductors on the circumference from breaking up, a plurality of tape members are made to adhere to the plane coil. In this connection, the plane coil to which the plurality of tape members are made to adhere is electrically connected with the electrode terminal of the semiconductor element and the terminal of the plane coil.
In this case, when the plane coil is separated from the inside frame and the outside frame, even if the support sections and connecting pieces are cut off, the conductors of the plane coil are fixed by the tape members. Therefore, the conductors on the circumference can be prevented from breaking up. Accordingly, the plane coil can be handled more easily.
However, it has been found that since the tape members are only adhered to the surfaces of the conductors of the plane coil, the IC card, made by inserting the plane coil just separated from the inside frame and the outside frame, into a space between a pair of resin films made of, e.g. PCV, and characters or others are provided on a surface thereof, has a relatively high thickness.
On the other hand, in the above-mentioned lead frame for an IC card, as shown in FIGS. 10(a) and 10(b), a semiconductor element 216 is mounted on a recessed portion 220 formed on the lower surfaces of the conductors 203 of the respective circumferences of the plane coil 202. The electrode terminals 216a and 216a of the semiconductor element 216 are electrically connected to the respective terminals 205, 205 of the conductor 203 by means of wires 218, 218, respectively. If the top portions of the loops of the wires 218, 218 protrude upward from the region of the conductor 203, the thickness of the final product of the IC card would be increased. Therefore, it is necessary to arrange the wires 218, 218 so as not to protrude from the loops of the wires 218f 218. Thus, there is a limit to reducing the thickness of the IC card.
On the other hand, in the case where the plane coil is formed by etching or punching a thin metal sheet, if the thickness of the metal sheet to which etching or punching is applied is reduced, the etching or punching operation is made easier.
An object of the present invention is to provide a non-contact type IC card and a method of manufacturing such a card.
According to the present invention, there is provided a non-contact type IC card comprising: a plane coil comprising a conductor line wound several times on a substantially the same surface, the plane coil having respective terminals at innermost and outermost ends; a semiconductor element having electrode terminals electrically connected to the terminals of the plane coil, respectively; and a resin-filled portion defined by at least a part of circumference of the plane coil where spaces between adjacent conductors of the plane coil are filled with light-setting resin to maintain predetermined intervals between the adjacent conductors of the plane coil.
The spaces between the adjacent conductors are filled with light-setting resin so as not to protrude from upper and lower surfaces, respectively, of the plane coil.
The plane coil is formed by punching or etching a thin metal plate in such a manner that a conductor line is wound several times on substantially the same surface.
According to another aspect of the present invention, there is provided a method of manufacturing a non-contact type IC card, comprising the following steps of:
forming a plane coil by punching or etching a thin metal plate in such a manner that a conductor line is wound several times on substantially the same surface, the plane coil having respective terminals at innermost and outermost ends, and adjacent loops of conductor line are connected to each other at predetermined positions by connecting pieces;
filling spaces between adjacent loops of conductor of the plane coil are filled with a light-setting resin to maintain predetermined intervals between the adjacent loops of conductors of the plane coil; and
removing the connecting pieces from the plane coil.
The space between adjacent loops of conductors are filled with light-setting resin so as not to protrude from upper and lower surfaces, respectively, of the plane coil.
The spaces between adjacent loops of conductor of the plane coil are filled with a light-setting resin at positions other than the positions of the connecting pieces.
The method of manufacturing a non-contact type IC card further comprises the following steps of:
forming a plane coil by punching or etching a thin metal plate in such a manner that a conductor line is wound several times on substantially the same surface, the plane coil having respective terminals at innermost and outermost ends, one of the terminals having a frame in which an accommodation hole is provided; and placing a semiconductor element having electrode terminals in the accommodation hole and electrically connecting the electrode terminals of the semiconductor element to the terminals of the plane coil.
The plane coil is provided at the innermost terminal thereof with the frame extending toward the inside of the plane coil, and the semiconductor element is accommodated in the accommodation hole of the frame of the innermost terminal.
The electrode terminals of the semiconductor element are electrically connected to the terminals of the plane coil, respectively, by means of wiring pattern which is formed on a surface of an insulating resin film.